JP02-106165 and JP2002-101657 disclose a DC-DC converter having a switching element which is driven to interrupt an input DC voltage for providing a regulated DC voltage to a load. The converter is equipped with a snubber circuit for reducing a surge voltage developed across the switching element. The snubber circuit is arranged to absorb the surge energy to be applied across the switching element and returning to the input DC voltage source in an attempt to reduce the surge voltage across the switching element for protection of the switching element as well as to reuse the energy for the load.
This scheme, however, is found to be insufficient for effectively feeding back the surge energy to the load and therefore not satisfactory for reducing the surge voltage being applied to the switching element, particularly when the converter is required to give a high output power to the load.